Storage Area Networks (SANs) provide an important data storage solution for modern data centers. SANs are primarily used to enhance storage devices accessibility to servers so that the devices appear like locally attached devices to the operating system. Examples of the storage devices include Redundant Array of Independent Disks (RAID) and disk arrays such as SAN arrays. By providing block-level storage that can be accessed by any networked servers, SANs provide a consolidated data storage while offering increased system performance.
SANs also offer excellent capacities for data backup and disaster recovery. Because data can be transferred between storage devices without interacting with a server, a SAN can accelerate the data backup process and conserve the processing power of the server Central Processing Unit (CPU).
Among various protocols that enable SANs, serial attached small computer system interface (SAS) offers point-to-point serial connections with high-throughput data communication. A SAS expander, similar to a switch, connects host devices such as host bus adaptors (HBAs) and target storage devices such as hard disk drives (HDDs).